‘‘Certainly in my own case, the attacks have gone down quite considerably.

‘‘I think that’s generally true across the scientific community.’’

Professor Steffen said it was at its worst in public meetings as he toured the nation explaining the carbon pricing but since then scientists had noted a ‘‘marked decrease in attacks and angst’’ over climate change.

He warned that the extreme weather that rocked Australia recently was ‘‘simply unprecedented’’ and wasn’t just natural patterns of drought and hot weather, but like an athlete on steroids.

‘‘It’s the same athlete, and they’re doing the same sport, but suddenly their performance gets better,’’ he told senators.

More extreme weather would occur in the future, and more intensely, he added.

The head of the Bureau of Meteorology Rob Vertessy echoed these warnings, saying average temperatures could be six degrees hotter by the end of the century if action isn’t taken.

‘‘Australia is definitely heating up, as is the rest of the world,’’ Dr Rob Vertessy said.